色甘酸钠预防哮喘发作的主要机制是
A.直接松弛支气管平滑肌B.稳定肥大细胞膜,抑制过敏介质释放C.阻断腺苷受体D.促进儿茶酚胺释放E.激动β受体
参考答案:B
为宣传维新变法,康有为、梁启超创办了
A.《万国公报》
B.《民报》
C.《每周评论》
D.《新青年》
People throughout the world are eating ______ meat per person as they did in 1950. A. more than twice B. twice much as C. twice as muchD. twice more